Small form-factor pluggable transceiver cage

ABSTRACT

A small form-factor pluggable metal cage has two sidewalls, a sidewall cover, a top plate, a soleplate and rear cover, which are made of a single piece of metal plate. Two types of legs extend from the cage, one being compliant type for extending through the board holes defined in a printed circuit board (PCB) and the other being piggy type abutting against the board. The compliant legs define two arc sections for stability and preventing the cage from disengaging from the PCB during the course of reflowing. The rear cover includes an inner panel extending from the second sidewall with a tab formed on a free end to engage a notch defined in the first sidewall. An outer panel extends from the top plate. The outer panel defines a slot for engaging a clasp of the inner panel. Two patches respectively extend from the sidewalls and are located above the inner panel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a small form-factor pluggable (SFP)optic transceiver module for fiber channel applications and, moreparticularly, to an optical transceiver module cage of high datatransfer rate program GBIC.

2. The Related Art

Transceiver modules provide bi-directional transmission of data betweenan electrical interface and an optical data link. The module receivesand converts electrically encoded data signals into optical signalswhich are then transmitted over the optical data link. Likewise, themodule receives and converts optically encoded data signals intoelectrical signals and transmit the electrical signals in the electricalinterface.

Normally, the transceiver module is mounted on a printed circuit board(PCB) assembly of a host computer, an input/output system, a peripheraldevice, or a switch. A small form-factor pluggable module connects witha metal cage assembly mounted on the PCB. The metal cage allows bothease of interconnection and ease of installation on PCB. The cagefunctions to dissipate electrostatics and serves as an electromagneticshield.

The metal cage generally has two parallel sidewalls, a rectangular top,a rectangular bottom, and opposite ends. A conventional cage employs atwo piece design. The two piece cage does not process a sufficientmechanical strength. Furthermore, the two piece design makes itdifficult to manufacture and install the cage. In addition, the priorart cage forms legs for supporting the cage. However, no board lockingmechanism is provided so that during the course of reflowing of asoldering process, the cage may inadvertently disengage from a PCB,causing poor soldering result.

SUMMARY OF THE INVENTION

To solve the problems of the prior art, the present invention provides asmall form-factor pluggable metal cage employing a one-piece design andthe cage of the present invention has two types of legs. The first typeis compliant legs that can be assembled through a board. The second typeis piggy legs which does not go through the board.

Accordingly, an object of the present invention is to provide a smallform-factor pluggable metal cage having compliant legs, each defining anarc portion for preventing the cage from disengaging from a printedcircuit board during the course of reflowing.

It is further object of the present invention is to provide a smallform-factor pluggable metal cage that enhances assembly.

It is another object of the present invention to provide a metal cage ofan optical transceiver having a one-piece structure which providesexcellent mechanical stability.

It is still another object of the present invention to provide a metalcage structure of a small form-factor pluggable which enhances automatedproduction and thus reduces costs of production.

Other objects, advantages and novel features of the present inventionwill be apparent from the following detailed description of preferredembodiments thereof with reference to the attached drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an optical transceiver cage constructedin accordance with the present invention;

FIG. 2 is a perspective view of the optical transceiver cage of thepresent invention in a partially opened condition;

FIG. 3 is similar to FIG. 1 with a portion of the cage removed;

FIG. 4 is another perspective view of FIG. 2;

FIG. 5 is perspective view of FIG. 1;

FIG. 6 is an enlarged view of encircled portion VI of FIG. 5 showinglegs of the cage of the present invention; and

FIG. 7 is a side elevational view of a portion of a sidewall of the cageconstructed in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-4, a small fact pluggable metal cage 1 inaccordance with the present invention comprises a first sidewall 2 a, asecond sidewall 2 b, a sidewall cover 3, a top plate 4, a soleplate 5, arear cover including an outer panel 6 and an inner panel 7 and two bulgepatches 8 a and 8 b which are made of a single piece of blank material,such as a metal plate. The one-piece structure adds additional strengthstability as compared with a prior art two piece metal cage.

Each of the sidewalls 2 a and 2 b forms two spring tabs 24 a, 24 bproximate a front end thereof and a plurality of compliant legs 22 andpiggy legs 23 at a lower edge thereof. The first sidewall 2 a also formsa plurality of resilient clasps 21. A small notch 25 is defined in arear edge of the first sidewall 2 a (FIG. 4).

Also referring to FIGS. 5, 6 and 7, in mounting the cage 1 to a printedcircuit board (PCB, not shown), the compliant legs 22 extend throughcorresponding holes defined in the board whereas the piggy legs 23 donot. Each piggy leg 23 comprises an elongate body 232 having a roundedend 231. Each compliant leg 22 comprises an arcuate body 222 having arounded end 221 substantially co-planar with the corresponding sidewall2 a, 2 b whereby the rounded end 221 is offset with respect to areference line in a first direction. The rounded end 221 is expanded sothat it extends laterally beyond the body 222 in a second directionopposite to the first direction. The arcuate end 221, once engaging thecorresponding hole of the PCB, help preventing the cage 1 fromdisengaging from the PCB during the course of reflowing. In theembodiment illustrated in FIG. 5, three compliant legs 22 are formed oneach sidewall 2 a, 2 b and there are six compliant legs 22 in totalamong which three are offset in a direction away from the inner panel 7of the rear cover of the cage 1, while the remaining compliant legs 22are offset in a direction toward the inner panel 7 of the rear cover ofthe cage 1. The combination of compliant legs 22 offset in differentdirections enhances interferential engagement of the legs 22 with thecorresponding holes of the PCB. Furthermore, the expanded ends 221 ofthe compliant legs 22 also serve as broad locks for securing the cage 1on the board. The piggy legs 23 act as standoff separating the cage 1from the PCB for enhancing soldering. The two types of legs make themetal cage 1 easy to connect to and install on a PCB.

Turning back to FIGS. 1-4, the top plate 4 forms spring tabs 41 at afront part thereof and defines a plurality of holes 42 at a rearportion. The sidewall cover 3 extends from the top plate 4 and overlapsthe first sidewall 2 a. The sidewall cover 3 defines openings 31, 32 forengaging the clasps 21 and the spring tab 24 a of the first sidewall 2a, thereby securing the sidewall cover 3 to the first sidewall 2 a,forming a parallelepiped cage.

The outer panel 6 of the rear cover extends from the top plate 4. Arectangular hole 61 is defined in the outer panel 6. The inner panelextends from the second sidewall 2 b has a free end. Legs 72 extend froma lower edge of the inner panel 7. The inner panel 7 forms a resilientclasp 71 engaging the rectangular hole 61 of the outer panel 6. A tab 73extends from the free edge of inner panel 7 opposite to the secondsidewall 2 b. The tab 73 engages the notch 25 of the first sidewall 2 a,thus securing the first sidewall 2 a and the outer panel 6 together.Patches 8 a and 8 b respectively extend from the first sidewall 2 a andthe second sidewall 2 b are located above the inner panel 7.

Referring to FIG. 5, the soleplate 5 is shorter than the top plate 4 andforms a central inward tab 52 and two grounding tabs 51 a and 51 b onopposite sides of the central tab 52. A central leg 53 proximate the tab52 and two legs 54 at a rear edge of the soleplate 5 extend from thesoleplate 5, also serving as standoffs.

While there have been shown and described what are at present consideredthe preferred embodiment of the invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing by the scope of the invention as defined bythe appended claims.

What is claimed is:
 1. A small form-factor pluggable transceiver cagecomprising: a top plate; a soleplate; a rear cover comprising an innerpanel and an outer panel; a sidewall cover and two sidewalls, wherebythe cage being made of a single piece of blank metallic material;wherein the inner panel extends from the second sidewall having a freeend opposite the second sidewall, the outer panel extending from the topplate; and wherein two types of legs extending out of the lower edge ofthe sidewalls, one being compliant leg adapted to extent through aprinted circuit board, and the other being piggy leg adapted to abutagainst printed circuit board.
 2. The cage as described in claim 1,wherein at least one of the compliant legs comprises first and secondarc portions, the curvature of the first arc portion being greater thanthe curvature of the second arc portion.
 3. The cage as described inclaim 2, wherein the second arc portions of the compliant legs beingselectively bent toward or away from the rear cover.
 4. A one-piecesmall form pluggable transceiver metal cage comprising: a top plate; asoleplate; a rear cover structure; a sidewall cover; first sidewall andsecond sidewall, wherein the rear cover structure comprises an innerpanel and an outer panel and two bulge patches for grounding; whereinthe inner panel extends from the second sidewall having a free endopposite the second sidewall, the outer panel extending from the topplate; wherein the first sidewall defines a notch in a rear edgethereof, a projection extending from the free end of the inner panelengaging the notch to fix the inner panel to the first sidewall; andwherein the inner panel forms a resilient clasp and the outer paneldefines a rectangular hole for engaging the resilient clasp.
 5. The cageas described in claim 4, wherein the inner panel forms a plurality oflegs extending from a lower edge thereof.
 6. A one-piece pluggabletransceiver metal cage comprising: a top plate; a soleplate opposite tosaid top plate in a parallel relation therebetween; first and secondmutually parallel sidewalls positioned between said top plate and saidsoleplate, said first sidewall integrally connected to both said topplate and said soleplate while said second sidewall integrally connectedonly to the soleplate; a sidewall cover downwardly extending from oneedge of said top plate and at least partially overlapping said secondsidewall; and a rear cover including inner and outer panels, said innerpanel laterally integrally extending from a rear edge of one of saidfirst and second sidewalls toward the other of said first and secondsidewalls, and at a distal free end of said inner panel abutting againstsaid other of said first and second sidewalls, said outer paneldownwardly integrally extending from a rear edge of said top plate andat least partially overlapping said inner panel.
 7. The cage asdescribed in claim 6, wherein said soleplate defines an opening around arear portion thereof so that a rear edge of the soleplate is far spacedfrom the rear cover.
 8. The cage as described in claim 6, furtherincluding means for combining the inner panel and the outer panel, andmeans for combining the sidewall cover and the second sidewall.